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package main
import (
"fmt"
"os"
)
type Camera struct {
ImageWidth uint
ImageHeight uint
Centre Vec3
PDU Vec3
PDV Vec3
Pixel00 Vec3
AntiAliasing uint
MaxDepth uint
}
func NewCamera(w uint, ar float64, aa uint, md uint) (cam Camera) {
cam.ImageWidth = w;
cam.ImageHeight = uint(float64(cam.ImageWidth) / ar);
if cam.ImageHeight < 1 {
cam.ImageHeight = 1;
}
cam.AntiAliasing = aa;
cam.MaxDepth = md;
focal_length := 1.0;
viewport_height := 2.0;
viewport_width := viewport_height *
float64(cam.ImageWidth) /
float64(cam.ImageHeight);
cam.Centre = SplatVec3(0);
viewport_u := Vec3{viewport_width, 0, 0};
viewport_v := Vec3{0, -viewport_height, 0};
cam.PDU = viewport_u.Div(SplatVec3(float64(cam.ImageWidth)));
cam.PDV = viewport_v.Div(SplatVec3(float64(cam.ImageHeight)));
viewport_upperleft := cam.Centre.
Sub(Vec3{0, 0, focal_length}).
Sub(viewport_u.Div(SplatVec3(2))).
Sub(viewport_v.Div(SplatVec3(2)));
cam.Pixel00 = viewport_upperleft.
Add(cam.PDU.Add(cam.PDV).Div(SplatVec3(2)));
return;
}
func (cam Camera) Render(world Hittable) {
fmt.Printf("P3\n%d %d\n255\n", cam.ImageWidth, cam.ImageHeight);
for row := uint(0); row < cam.ImageHeight; row++ {
fmt.Fprintf(os.Stderr,
"[GScanlines remaining: %3d...",
(cam.ImageHeight - row));
for col := uint(0); col < cam.ImageWidth; col++ {
pixel_colour := SplatVec3(0);
for i := uint(0); i < cam.AntiAliasing; i++ {
r := cam.GetRay(row, col);
pixel_colour = pixel_colour.Add(r.Colour(world, cam.MaxDepth));
}
pixel_colour = pixel_colour.
Div(SplatVec3(float64(cam.AntiAliasing)));
fmt.Printf("%s ", pixel_colour.ToPPM());
}
fmt.Printf("\n");
}
}
func (cam Camera) GetRay(row uint, col uint) Ray {
offset := unit_square();
pixel_sample := cam.Pixel00.
Add(cam.PDU.Mul(SplatVec3(float64(col) + offset.X))).
Add(cam.PDV.Mul(SplatVec3(float64(row) + offset.Y)));
return Ray{cam.Centre, pixel_sample.Sub(cam.Centre)};
}
func unit_square() Vec3 {
i := Interval{-0.5, 0.5};
return Vec3{i.Sample(), i.Sample(), 0};
}
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